Scouring composition

ABSTRACT

According to the present invention there is provided a composition suitable for removing metal stains, for example rust stains from hard surfaces comprising C1-6 carboxylic acid and an abrasive particulate component having hardness from 2 to 4 as measured according to the MOHS scale.

TECHNICAL FIELD

[0001] The present invention relates to scouring composition suitable for use in cleaning hard surfaces, especially rust stains from hard surfaces.

BACKGROUND

[0002] Scouring compositions such as those particulate compositions or liquid, gel, paste-type compositions containing abrasive components are well known in the art. Such compositions are used for cleaning hard surfaces, especially those surfaces that tend to become soiled with mineral deposits for example kitchen and/or bathroom surfaces.

[0003] Scouring compositions may also find use in removing metal stains from surfaces. More particularly, some scouring compositions are marketed as being capable of removing rust stains from surfaces. It has been noted by the Applicant, especially in less developed countries were poor water piping is still in existence, that metal oxidation products, for example, rust collects or deposits in the pipe and then flows with the water out of the water outlet pipe onto the surface in the home. The metal deposit collects on the surface leaving a sometimes coloured stain. Such metal-based stains are difficult to remove with general household hard surface cleaner and require specialist treatment with, for example a rust removing composition.

[0004] The Applicants have further found that although compositions containing abrasives go some way in removing the metal-based stain, such compositions can scratch or otherwise harm the surface to which it is applied. Thus it has been our objective to find a composition that is not only capable of removing metal stains, especially rust stains, but also does not scratch or otherwise harm the surface to which it is applied to the same extent as those commonly available.

[0005] An additional advantage of the present invention is that the composition also provides good cleaning performance. Moreover the compositions of the present invention also provide limescale and other mineral deposit removal.

[0006] Yet a further advantage of the compositions of the present invention is that they may be used on any hard surface. By “hard-surfaces”, it is meant herein any kind of surfaces typically found in houses like kitchens, bathrooms, or in car interiors or exteriors, e.g., floors, walls, tiles, windows, sinks, showers, shower plastified curtains, wash basins, WCs, dishes, fixtures and fittings and the like made of different materials like ceramic, vinyl, no-wax vinyl, linoleum, melamine, glass, any plastics, plastified wood, metal or any painted or varnished or sealed surface and the like. Hard-surfaces also include household appliances including, but not limited to, refrigerators, freezers, washing machines, automatic dryers, ovens, microwave ovens, dishwashers and so on.

SUMMARY OF THE INVENTION

[0007] The present invention relates to a scouring composition comprising a C1-6 carboxylic acid and an abrasive particulate component having hardness from 2 to 4 as measured according to the MOHS hardness scale.

[0008] In a further aspect, the present invention relates to a process for manufacturing a composition as described in the preceding sentence.

[0009] In a yet a further aspect, the present invention relates to a process of treating a hard surface comprising the steps of contacting the hard surface with a scouring composition comprising a C1-6 carboxylic acid and an abrasive particulate component having hardness from 2 to 4 as measured according to the MOHS scale.

[0010] In a yet a further aspect, the present invention relates to the use of a composition comprising oxalic acid and calcium carbonate to remove rust stains from a hard surface.

DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention relates to a scouring composition comprising a C1-6 carboxylic acid and an abrasive particulate component having hardness from 2 to 4 as measured according to the MOHS hardness scale. By “scouring composition” it is meant a composition being in particulate, liquid or gel-type composition comprising an abrasive component. More preferably the composition is particulate.

[0012] For reasons of storage stability and flow it is preferred that the level of water in the composition is limited to a level of less than 10%, more preferably less than 5%, most preferably less than 2% water in the composition. The pH of the composition on mixing with water is typically in the acidic range of pH less than 7, more preferably the pH is less than 4, even more preferably less than 2. According to the present invention pH is measured of a 25% dispersion of the composition in distilled water.

[0013] The compositions of the present invention comprises a C1-6 carboxylic acid, meaning a carboxylic acid comprising from 1 to 6 carbon atoms as an essential feature thereof. Suitable acids may preferably be mono, but are preferably dicarboxylic acids. Suitable acids are selected form the group consisting of formic acid, sulphamic acid, hydroxyacetic acid, citric acid, fumaric acid, maleic acid, glycolic acid, lactic acid, thioglycolic acid, thiomalic acid, oxalic acid and mixtures thereof.

[0014] The most preferred acid is oxalic acid since it is capable of providing rust removal by not only reducing the pH of the composition in water to a level where solubilisation of rust stains is improved, but also acts as a chelating agent for Fe³⁺ ions. Oxalic acid suitable for use herein can be in anhydrous form, dihydrate from, mixtures of the preceding forms and intermediate forms of the drying process from dihydrate to anhydrous (as described in Kirk-Othmer, 3^(rd) Edition Vol 16, page 618.) and are also preferably in particulate form. The anhydrous form of oxalic acid is the most preferred in terms of performance and stability, even more preferred is the Alfa crystalline structure over the Beta structure. However the anhydrous form of oxalic acid is expensive and thus from a practical point of view the dihydrate form is preferred for use in the compositions of the present invention. Suitable oxalic acid dihydrate comprises less than 30% water, more preferably less than 15% water and even more preferably less than 10%water. The most preferred oxalic acid dihydrate for use herein comprises from 5-9% water. Although not wishing to be bound by theory it is thought preferable to limit the amount of water in the composition so as to prevent premature reaction of the oxalic acid and carbonate during storage. Oxalic acid dihydrate is available in particulate form from Allied Corporation, Rhone-Poulenc etc

[0015] The oxalic acid is preferably present in the composition at a level of from 5% to 50%, more preferably from 5% to 30% and most preferably from 8% to 16%.

[0016] Abrasive components typically used in the past include silica, silicate, shale ash, perlite and quartz sand. However the Applicants have found that such abrasives as known and typically used in the art, when used to clean hard surfaces, leave visible scratch marks on the surface. Scratches on the surface, are visually and sensuously unpleasant, reduce shine and can weaken the surface, potentially leading to further damage.

[0017] The composition of the present invention employs an abrasive component having hardness of 2 to 4 as measured according to MOHS hardness scale. The MOHS hardness scale is an internationally recognised scale for measuring the hardness of a compound versus a compound of known hardness, see Encyclopedia of Chemical Technology, Kirk-Othmer, 4^(th) Edition Vol 1, page 18 or Lide, D. R (ed) CRC Handbook of Chemistry and Physics, 73^(rd) edition, Boca Raton, Fla.: The Rubber Company, 1992-1993. The abrasive component is substantially insoluble or partially soluble in water. Most preferably the abrasive component is calcium carbonate.

[0018] The abrasive component preferably has average particle size of less than 300 microns, more preferably less than 100 microns and most preferably from 5 to 100 microns.

[0019] The abrasive component is preferably present in the composition in sufficient amount to provide an abrasive action. More Preferably the abrasive component in present at a level of from 50% to 99%, more preferably from 60% to 95% and most preferably from 75% to 90%.

[0020] Furthermore it has also been found that the preferred weight ratio of oxalic acid to carbonate is in the range of from 1:1 to 1:18, more preferably from 1:6 to 1:9 and most preferably from 1:7 to 1:8.

Process of Preparing the Composition

[0021] Also claimed herein is a process of preparing the composition of the present invention. The process requires the steps of premixing the abrasive and any wet or water-containing ingredients; drying the premix formed in the preceding step to achieve a composition having a moisture content of less than 10%, preferably less than 5% water; and subsequently mixing the substantially dry premix with the carboxylic acid, preferably oxalic acid.

[0022] In a preferred embodiment where pigment and/or perfume are present these ingredients are preferably added in additional step preceding the step of mixing the abrasive with the wet or water-containing ingredients. In this preceding step, a proportion of the abrasive is mixed with the perfume and pigment in order to achieve a homogenous distribution of perfume and/or pigment. Where the pigment is available in particulate form, a preferably 5% solution of pigment in water is mixed with the abrasive.

[0023] The second step requires the drying of the premix. Drying can be achieved passively by allowing moisture to evaporate or actively using any suitable equipment and method. The premix is dried to a point whereby it contains less than 10% water, more preferably less than 5% water at this point the premix is said to be “substantially dry”. The substantially dry premix is then mixed with the oxalic acid.

[0024] Additional optional ingredients, dry or substantially dry ingredients, can be added before or after the drying step, but must not have the effect of increasing the water content of the composition to higher than 10% water. In a preferred embodiment all additional ingredients namely wet, water-containing, dry or substantially dry ingredients are added to the composition prior to the drying step.

Optional Ingredients

[0025] The compositions of the present invention may include one or more optional ingredients. Such optional ingredients may be selected from the group consisting of surfactants, inorganic acids, chelating agents, reducing agents, perfume and colouring agent

Surfactants

[0026] The compositions of the present invention optionally although preferably comprise a surfactant. Surfactants provide additional cleaning performance benefits by removing a number of different types of soils for example greasy, oily soils. It has also been seen by the Applicants that due to the reaction of especially carbonate and oxalic acid, the evolution of gas, CO₂, in combination with a surfactant results in the formation of foam. The presence of foam is aesthetically pleasing to consumers, which is then related to cleaning performance.

[0027] Preferred surfactants are selected from the group consisting of nonionic, anionic, cationic, zwitterionic, amphoteric surfactants and mixtures thereof.

[0028] Where present such surfactants may be present in the composition according to the present invention in amounts of from 0.1% to 50%, preferably of from 0.1% to 20% and more preferably of from 1% to 10% by weight of the total composition.

[0029] Suitable anionic surfactants for use in the compositions herein include water-soluble salts or acids of the formula ROSO₃M wherein R preferably is a C₁₀-C₂₄ hydrocarbyl, preferably an alkyl or hydroxyalkyl having a C₁₀-C₂₀ alkyl component, more preferably a C₁₂-C₁₈ alkyl or hydroxyalkyl, and M is H or a cation, e.g., an alkali metal cation (e.g., sodium, potassium, lithium), or ammonium or substituted ammonium (e.g., methyl-, dimethyl-, and trimethyl ammonium cations and quaternary ammonium cations, such as tetramethyl-ammonium and dimethyl piperdinium cations and quaternary ammonium cations derived from alkylamines such as ethylamine, diethylamine, triethylamine, and mixtures thereof, and the like). Typically, alkyl chains of C₁₂-₁₆ are preferred for lower wash temperatures (e.g., below about 50° C.) and C₁₆-₁₈ alkyl chains are preferred for higher wash temperatures (e.g., above about 50° C.).

[0030] Other suitable anionic surfactants for use herein are water-soluble salts or acids of the formula RO(A)_(m)SO₃M wherein R is an unsubstituted C₁₀-C₂₄ alkyl or hydroxyalkyl group having a C₁₀-C₂₄ alkyl component, preferably a C₁₂-C₂₀ alkyl or hydroxyalkyl, more preferably C₁₂-C₁₈ alkyl or hydroxyalkyl, A is an ethoxy or propoxy unit, m is greater than zero, typically between about 0.5 and about 6, more preferably between about 0.5 and about 3, and M is H or a cation which can be, for example, a metal cation (e.g., sodium, potassium, lithium, calcium, magnesium, etc.), ammonium or substituted-ammonium cation. Alkyl ethoxylated sulfates as well as alkyl propoxylated sulfates are contemplated herein. Specific examples of substituted ammonium cations include methyl-, dimethyl-, trimethyl-ammonium and quaternary ammonium cations, such as tetramethyl-ammonium, dimethyl piperdinium and cations derived from alkanolamines such as ethylamine, diethylamine, triethylamine, mixtures thereof, and the like. Exemplary surfactants are C₁₂-C₁₈ alkyl polyethoxylate (1.0) sulfate, C₁₂-C₁₈E(1.0)M), C₁₂-C₁₈ alkyl polyethoxylate (2.25) sulfate, C₁₂-C₁₈E(2.25)M), C₁₂-C₁₈ alkyl polyethoxylate (3.0) sulfate C₁₂-C₁₈E(3.0), and C₁₂-C₁₈ alkyl polyethoxylate (4.0) sulfate C₁₂-C₁₈E(4.0)M), wherein M is conveniently selected from sodium and potassium.

[0031] Other particularly suitable anionic surfactants for use herein are alkyl sulphonates including water-soluble salts or acids of the formula RSO₃M wherein R is a C₆-C₂₂ linear or branched, saturated or unsaturated alkyl group, preferably a C₁₂-C₁₈ alkyl group and more preferably a C₁₄-C₁₆ alkyl group, and M is H or a cation, e.g., an alkali metal cation (e.g., sodium, potassium, lithium), or ammonium or substituted ammonium (e.g., methyl-, dimethyl-, and trimethyl ammonium cations and quaternary ammonium cations, such as tetramethyl-ammonium and dimethyl piperdinium cations and quaternary ammonium cations derived from alkylamines such as ethylamine, diethylamine, triethylamine, and mixtures thereof, and the like).

[0032] Suitable alkyl aryl sulphonates for use herein include water- soluble salts or acids of the formula RSO₃M wherein R is an aryl, preferably a benzyl, substituted by a C₆-C₂₂ linear or branched saturated or unsaturated alkyl group, preferably a C₁₂-C₁₈ alkyl group and more preferably a C₁₂-C₁₆ alkyl group, and M is H or a cation, e.g., an alkali metal cation (e.g., sodium, potassium, lithium, calcium, magnesium etc) or ammonium or substituted ammonium (e.g., methyl-, dimethyl-, and trimethyl ammonium cations and quaternary ammonium cations, such as tetramethyl-ammonium and dimethyl piperdinium cations and quaternary ammonium cations derived from alkylamines such as ethylamine, diethylamine, triethylamine, and mixtures thereof, and the like). The most preferred surfactant in terms of performance is an anionic surfactant according to the above formula wherein R is benzyl substituted with a C12 alkyl group and M is Hydrogen i.e. linear C12 alkyl benzene sulphonate (HLAS).

[0033] The alkylsulfonates and alkyl aryl sulphonates for use herein include primary and secondary alkylsulfonates and primary and secondary alkyl aryl sulphonates. By “secondary C6-C22 alkyl or C6-C22 alkyl aryl sulphonates”, it is meant herein that in the formula as defined above, the SO3M or aryl-SO3M group is linked to a carbon atom of the alkyl chain being placed between two other carbons of the said alkyl chain (secondary carbon atom).

[0034] Other anionic surfactants useful for detersive purposes can also be used herein. These can include salts (including, for example, sodium, potassium, ammonium, and substituted ammonium salts such as mono-, di- and triethanolamine salts) of soap, C₈-C₂₄ olefinsulfonates, sulfonated polycarboxylic acids prepared by sulfonation of the pyrolyzed product of alkaline earth metal citrates, e.g., as described in British patent specification No. 1,082,179, C₈-C₂₄ alkylpolyglycolethersulfates (containing up to 10 moles of ethylene oxide); alkyl ester sulfonates such as C₁₄-₁₆ methyl ester sulfonates; acyl glycerol sulfonates, fatty oleyl glycerol sulfates, alkyl phenol ethylene oxide ether sulfates, paraffin sulfonates, alkyl phosphates, isethionates such as the acyl isethionates, N-acyl taurates, alkyl succinamates and sulfosuccinates, monoesters of sulfosuccinate (especially saturated and unsaturated C₁₂-C₁₈ monoesters) diesters of sulfosuccinate (especially saturated and unsaturated C₆-C14 diesters), sulfates of alkylpolysaccharides such as the sulfates of alkylpolyglucoside (the nonionic nonsulfated compounds being described below), branched primary alkyl sulfates, alkyl polyethoxy carboxylates such as those of the formula RO(CH₂CH₂O)_(k)CH₂COO—M⁺wherein R is a C₈-C₂₂ alkyl, k is an integer from 0 to 10, and M is a soluble salt-forming cation. Resin acids and hydrogenated resin acids are also suitable, such as rosin, hydrogenated rosin, and resin acids and hydrogenated resin acids present in or derived from tall oil. Further examples are given in “Surface Active Agents and Detergents” (Vol. I and II by Schwartz, Perry and Berch). A variety of such surfactants are also generally disclosed in U.S. Pat. No. 3,929,678, issued Dec. 30, 1975, to Laughlin, et al. at Column 23, line 58 through Column 29, line 23 (herein incorporated by reference).

[0035] Other particularly suitable anionic surfactants for use herein are alkyl carboxylates and alkyl alkoxycarboxylates having from 4 to 24 carbon atoms in the alkyl chain, preferably from 8 to 18 and more preferably from 8 to 16, wherein the alkoxy is propoxy and/or ethoxy and preferably is ethoxy at an alkoxylation degree of from 0.5 to 20, preferably from 5 to 15. Preferred alkylalkoxycarboxylate for use herein is sodium laureth 11 carboxylate (i.e., RO(C₂H₄O)₁₀—CH₂COONa, with R=C12-C14) commercially available under the name Akyposoft® 100NV from Kao Chemical Gbmh.

[0036] Suitable amphoteric surfactants for use herein include amine oxides having the following formula R₁ R₂R₃NO wherein each of R1, R2 and R3 is independently a saturated substituted or unsubstituted, linear or branched hydrocarbon chain of from 1 to 30 carbon atoms. Preferred amine oxide surfactants to be used according to the present invention are amine oxides having the following formula R₁R₂R₃NO wherein R1 is an hydrocarbon chain comprising from 1 to 30 carbon atoms, preferably from 6 to 20, more preferably from 8 to 16, most preferably from 8 to 12, and wherein R2 and R3 are independently substituted or unsubstituted, linear or branched hydrocarbon chains comprising from 1 to 4 carbon atoms, preferably from 1 to 3 carbon atoms, and more preferably are methyl groups. R1 may be a saturated, substituted or unsubstituted linear or branched hydrocarbon chain. Suitable amine oxides for use herein are for instance natural blend C8-C10 amine oxides as well as C12-C16 amine oxides commercially available from Hoechst.

[0037] Suitable zwitterionic surfactants for use herein contain both a cationic hydrophilic group, i.e., a quaternary ammonium group, and anionic hydrophilic group on the same molecule at a relatively wide range of pH's. The typical anionic hydrophilic groups are carboxylates and sulfonates, although other groups like sulfates, phosphonates, and the like can be used. A generic formula for the zwitterionic surfactants to be used herein is:

R₁—N⁺(R₂)(R₃)R₄X⁻

[0038] wherein R₁ is a hydrophobic group; R₂ is hydrogen, C₁-C₆ alkyl, hydroxy alkyl or other substituted C₁-C₆ alkyl group; R₃ is C₁-C₆ alkyl, hydroxy alkyl or other substituted C₁ -C₆ alkyl group which can also be joined to R₂ to form ring structures with the N, or a C₁-C₆ carboxylic acid group or a C₁-C₆ sulfonate group; R₄ is a moiety joining the cationic nitrogen atom to the hydrophilic group and is typically an alkylene, hydroxy alkylene, or polyalkoxy group containing from 1 to 10 carbon atoms; and X is the hydrophilic group which is a carboxylate or sulfonate group.

[0039] Preferred hydrophobic groups R₁ are aliphatic or aromatic, saturated or unsaturated, substituted or unsubstituted hydrocarbon chains that can contain linking groups such as amido groups, ester groups. More preferred R₁ is an alkyl group containing from 1 to 24 carbon atoms, preferably from 8 to 18, and more preferably from 10 to 16. These simple alkyl groups are preferred for cost and stability reasons. However, the hydrophobic group R₁ can also be an amido radical of the formula R_(a)—C(O)—NH—(C(R_(b))2)m, wherein R_(a) is an aliphatic or aromatic, saturated or unsaturated, substituted or unsubstituted hydrocarbon chain, preferably an alkyl group containing from 8 up to 20 carbon atoms, preferably up to 18, more preferably up to 16, R_(b) is selected from the group consisting of hydrogen and hydroxy groups, and m is from 1 to 4, preferably from 2 to 3, more preferably 3, with no more than one hydroxy group in any (C(R_(b))2) moiety.

[0040] Preferred R₂ is hydrogen, or a C₁-C₃ alkyl and more preferably methyl. Preferred R₃ is a C₁-C₄ carboxylic acid group or C1-C4 sulfonate group, or a C₁-C₃ alkyl and more preferably methyl. Preferred R₄ is (CH2)_(n) wherein n is an integer from 1 to 10, preferably from 1 to 6, more preferably is from 1 to 3.

[0041] Suitable cationic surfactants for use herein include derivatives of quaternary ammonium, phosphonium, imidazolium and sulfonium compounds. Preferred cationic surfactants for use herein are quaternary ammonium compounds wherein one or two of the hydrocarbon groups linked to nitrogen are a saturated, linear or branched alkyl group of 6 to 30 carbon atoms, preferably of 10 to 25 carbon atoms, and more preferably of 12 to 20 carbon atoms, and wherein the other hydrocarbon groups (i.e. three when one hydrocarbon group is a long chain hydrocarbon group as mentioned hereinbefore or two when two hydrocarbon groups are long chain hydrocarbon groups as mentioned hereinbefore) linked to the nitrogen are independently substituted or unsubstituted, linear or branched, alkyl chain of from 1 to 4 carbon atoms, preferably of from 1 to 3 carbon atoms, and more preferably are methyl groups. Preferred quaternary ammonium compounds suitable for use herein are non-chloride/non halogen quaternary ammonium compounds. The counterion used in said quaternary ammonium compounds are compatible with any peracid and are selected from the group of methyl sulfate, or methylsulfonate, and the like.

[0042] Particularly preferred for use in the compositions of the present invention are trimethyl quaternary ammonium compounds like myristyl trimethylsulfate, cetyl trimethylsulfate and/or tallow trimethylsulfate. Such trimethyl quaternary ammonium compounds are commercially available from Hoechst, or from Albright & Wilson under the trade name EMPIGEN CM®.

[0043] Amongst the nonionic surfactants, alkoxylated nonionic surfactants are suitable for use herein.

[0044] Suitable alkoxylated nonionic surfactants are capped alkoxylated nonionic surfactants, especially capped ethoxylated nonionic surfactants, and non-capped alkoxylated nonionic surfactants, especially non-capped ethoxylated nonionic surfactants, or mixtures thereof

[0045] Suitable capped alkoxylated nonionic surfactants for use herein are according to the formula:

R₁ (O—CH₂—CH₂)n—(OR₂)m—O—R₃

[0046] wherein R₁ is a C₈-C₂₄ linear or branched alkyl or alkenyl group, aryl group, alkaryl group, preferably R₁ is a C₈-C₁₈ alkyl or alkenyl group, more preferably a C₁₀-C₁₅ alkyl or alkenyl group, even more preferably a C₁₀-C₁₅ alkyl group; wherein R₂ is a C₁-C₁₀ linear or branched alkyl group, preferably a C₂-C₁₀ linear or branched alkyl group; wherein R₃ is a C₁-C₁₀ alkyl or alkenyl group, preferably a C₁-C₅ alkyl group, more preferably methyl; and wherein n and m are integers independently ranging in the range of from 1 to 20, preferably from 1 to 10, more preferably from 1 to 5; or mixtures thereof.

[0047] Suitable non-capped alkoxylated nonionic surfactants are according to the formula RO—(A)_(n)—H, wherein : R is a C₈ to C₂₄, preferably a C₈ to C₁₈, more preferably a C₁₀ to C₁₆, even more preferably a C₁₃ to C₁₆, alkyl or alkenyl chain; A is an ethoxy or propoxy or butoxy unit; and wherein n is from 1 to 20, preferably from 1 to 15 and, more preferably from 2 to 15, even more preferably from 2 to 12 and most preferably 7; or mixtures thereof. Preferred R chains for use herein are the C₁₃ to C₁₆ alkyl chains. Non-capped ethoxy/butoxylated, ethoxy/propoxylated, butoxy/propoxylated and ethoxy/butoxy/propoxylated nonionic surfactants may also be used herein. Preferred non-capped alkoxylated nonionic surfactants are non-capped ethoxylated nonionic surfactants.

[0048] In a preferred embodiment according to the present invention the surfactant herein, when present, is a mixture of nonionic surfactants. Preferably, said surfactant is a mixture of alkoxylated nonionic surfactants, more preferably a mixture of non-capped ethoxylated nonionic surfactants, even more preferably a mixture of a C₁₄₋₁₆ EO7 non-capped ethoxylated nonionic surfactant and a C₁₃₋₁₅ EO7 non-capped ethoxylated nonionic surfactant

Inorganic Acids

[0049] Another optional component of the compositions of the present invention is an inorganic acid or generator thereof. Inorganic acids are preferred components as they are believed to provide a source of hydrogen ions and thus further reduce the pH of the composition in aqueous environment, for example when the particulate composition is in contact with water.

[0050] Reducing the pH of the composition in use in the presence of water aids the removal of metal stains, especially rust stains. Although not wishing to be bound by theory it is believed that iron oxide (rust) is more water soluble at low pH and thus the lower pH the greater then removal of rust stain from the surface.

[0051] Suitable inorganic acids include all those capable of providing a pH as stated above. More preferred inorganic acids are selected from the group consisting of phosphoric acid, hydrochloric acid, ammonium bifluride and further acids generated therefrom in situ and sulfuric acid.

Chelating Agents

[0052] Another class of optional compounds for use herein include chelating agents or mixtures thereof. Chelating agents can be incorporated in the compositions herein in amounts ranging from 0.0% to 10.0% by weight of the total composition, preferably 0.1% to 5.0%. Chelating agents can be beneficial in the composition herein as a means of complexing metal ions from the metal ion stain. Suitable complexing agents include any having an affinity for stain-causing metal ions, for example Fe³⁺.

[0053] Suitable chelating agents for use herein include the phosphonate chelating agents. Phosphonate chelating agents are those selected from the group consisting of alkali metal ethane 1-hydroxy diphosphonates (HEDP), alkylene poly (alkylene phosphonate), as well as amino phosphonate compounds, including amino aminotri(methylene phosphonic acid) (ATMP), nitrilo trimethylene phosphonates (NTP), ethylene diamine tetra methylene phosphonates, and diethylene triamine penta methylene phosphonates (DTPMP). The phosphonate compounds may be present either in their acid form or as salts of different cations on some or all of their acid functionalities. Preferred phosphonate chelating agents to be used herein are diethylene triamine penta methylene phosphonate (DTPMP) and ethane 1-hydroxy diphosphonate (HEDP). Such phosphonate chelating agents are commercially available from Monsanto under the trade name DEQUEST®.

[0054] Polyfunctionally-substituted aromatic chelating agents may also be useful in the compositions herein. See U.S. Pat. No. 3,812,044, issued May 21, 1974, to Connor et al. Preferred compounds of this type in acid form are dihydroxydisulfobenzenes such as 1,2-dihydroxy -3,5-disulfobenzene.

[0055] A preferred biodegradable chelating agent for use herein is ethylene diamine -N,N′- disuccinic acid, or alkali metal, or alkaline earth, ammonium or substitutes ammonium salts thereof or mixtures thereof. Ethylenediamine N,N′- disuccinic acids, especially the (S,S) isomer have been extensively described in U.S. Pat. No. 4, 704, 233, Nov. 3, 1987, to Hartman and Perkins. Ethylenediamine N,N′- disuccinic acids is, for instance, commercially available under the tradename ssEDDS® from Palmer Research Laboratories.

[0056] Suitable amino carboxylates for use herein include ethylene diamine tetra acetates, diethylene triamine pentaacetates, diethylene triamine pentaacetate (DTPA), N-hydroxyethylethylenediamine triacetates, N-hydroxyethylethylenediamine triacetic acid (HEDTA), nitrilotri-acetates, ethylenediamine tetrapropionates, triethylenetetraaminehexa-acetates, ethanol-diglycines, propylene diamine tetracetic acid (PDTA) and methyl glycine di-acetic acid (MGDA), both in their acid form, or in their alkali metal, ammonium, and substituted ammonium salt forms. Particularly suitable amino carboxylates to be used herein are diethylene triamine penta acetic acid, propylene diamine tetracetic acid (PDTA) which is, for instance, commercially available from BASF under the trade name Trilon FS® and methyl glycine di-acetic acid (MGDA).

[0057] Further carboxylate chelating agents for use herein include salicylic acid, aspartic acid, glutamic acid, glycine, malonic acid or mixtures thereof.

Reducing Agents

[0058] Another optional ingredient of the composition as described herein is a reducing agent. A further aid for removing metal ion-based stains may be to reduce the metal ion to a more oxidised state. For example a composition comprising a reducing agent will reduce Fe³⁺to Fe²⁺which is more water soluble than the Fe³⁺ion.

[0059] Any reducing agent known in the art capable of reducing a metal ion and being compatible with at least the essential ingredients of the present compositions are preferred herein. The most preferred reducing agent are ascorbic acid, bisulfite, thiourea and mixtures thereof.

Moisture Trap

[0060] The compositions of the present invention may also, preferably comprise a moisture trap as an optional ingredient. By moisture trap it is meant, a hygroscopic compound that readily absorbs moisture/water from it's surroundings. Suitable moisture traps may be any of those commonly known in the art and compatible with the essential ingredients herein. Preferred examples of moisture traps include silicagel, sodium acetate and mixtures thereof.

Perfumes

[0061] Suitable perfumes for use herein include materials which provide an olfactory aesthetic benefit and/or cover any “chemical” odour that the product may have. The main function of a small fraction of the highly volatile, low boiling (having low boiling points), perfume components in these perfumes is to improve the fragrance odor of the product itself, rather than impacting on the subsequent odor of the surface being cleaned. However, some of the less volatile, high boiling perfume ingredients provide a fresh and clean impression to the surfaces, and it is desirable that these ingredients be deposited and present on the dry surface. Perfume ingredients can be readily solubilized in the compositions, for instance by the amphoteric surfactant. The perfume ingredients and compositions suitable to be used herein are the conventional ones known in the art. Selection of any perfume component, or amount of perfume, is based solely on aesthetic considerations. Typically the compositions herein may comprise a perfume ingredient, or mixtures thereof, in amounts up to 5.0%, more preferably in amounts of 0.1% to 1.5% by weight of the total composition.

Builders

[0062] The liquid compositions of the present invention may also comprises a builder or a mixture thereof, as an optional ingredient. Suitable builders for use herein include polycarboxylates and polyphosphates, and salts thereof. Typically, the compositions of the present invention comprise up to 20.0 % by weight of the total composition of a builder or mixtures thereof, preferably from 0.1% to 10.0%, and more preferably from 0.5% to 5.0%.

[0063] Suitable and preferred polycarboxylates for use herein are organic polycarboxylates where the highest LogKa, measured at 25° C./0.1 M ionic strength is between 3 and 8, wherein the sum of the LogKCa+LogKMg, measured at 25° C./0.1 M ionic strength is higher than 4, and wherein LogKCa=LogKMg±2 units, measured at 25° C./0.1 M ionic strength.

[0064] Such suitable and preferred polycarboxylates include citrate and complexes of the formula:

CH(A)(COOX)—CH(COOX)—O—CH(COOX)—CH(COOX)(B)

[0065] wherein A is H or OH; B is H or —O—CH(COOX)—CH₂(COOX); and X is H or a salt-forming cation. For example, if in the above general formula A and B are both H, then the compound is oxydissuccinic acid and its water-soluble salts. If A is OH and B is H, then the compound is tartrate monosuccinic acid (TMS) and its water-soluble salts. If A is H and B is —O—CH(COOX)—CH₂(COOX), then the compound is tartrate disuccinic acid (TDS) and its water-soluble salts. Mixtures of these builders are especially preferred for use herein. Particularly TMS to TDS, these builders are disclosed in U.S. Pat. No. 4,663,071, issued to Bush et al., on May 5, 1987.

[0066] Still other ether polycarboxylates suitable for use herein include copolymers of maleic anhydride with ethylene or vinyl methyl ether, 1, 3, 5-trihydroxy benzene-2, 4, 6-trisulfonic acid.

[0067] Other useful polycarboxylate builders include the ether hydroxypolycarboxylates represented by the structure:

HO—[C(R)(COOM)—C(R)(COOM)—O]_(n)—H

[0068] wherein M is hydrogen or a cation wherein the resultant salt is water-soluble, preferably an alkali metal, ammonium or substituted ammonium cation, n is from about 2 to about 15 (preferably n is from about 2 to about 10, more preferably n averages from about 2 to about 4) and each R is the same or different and selected from hydrogen, C₁₋₄ alkyl or C₁₋₄ substituted alkyl (preferably R is hydrogen).

[0069] Suitable ether polycarboxylates also include cyclic compounds, particularly alicyclic compounds, such as those described in U.S. Pat. Nos. 3,923,679; 3,835,163; 4,158,635; 4,120,874 and 4,102,903, all of which are incorporated herein by reference.

[0070] Preferred amongst those cyclic compounds are dipicolinic acid and chelidanic acid.

[0071] Also suitable polycarboxylates for use herein are mellitic acid, succinic acid, polymaleic acid, benzene 1,3,5-tricarboxylic acid, benezene pentacarboxylic acid, and carboxymethyloxysuccinic acid, and soluble salts thereof.

[0072] Still suitable carboxylate builders herein include the carboxylated carbohydrates disclosed in U.S. Pat. No. 3,723,322, Diehl, issued Mar. 28, 1973, incorporated herein by reference.

[0073] Other suitable carboxylates for use herein, but which are less preferred because they do not meet the above criteria are alkali metal, ammonium and substituted ammonium salts of polyacetic acids. Examples of polyacetic acid builder salts are sodium, potassium, lithium, ammonium and substituted ammonium salts of ethylenediamine, tetraacetic acid and nitrilotriacetic acid.

[0074] Other suitable, but less preferred polycarboxylates are those also known as alkyliminoacetic builders such as methyl imino diacetic acid, alanine diacetic acid, methyl glycine diacetic acid, hydroxy propylene imino diacetic acid and other alkyl imino acetic acid builders.

[0075] Also suitable in the compositions of the present invention are the 3,3-dicarboxy-4-oxa-1,6-hexanediotes and the related compounds disclosed in U.S. Pat. No. 4,566,984, Bush, issued Jan. 28, 1986, incorporated herein by reference. Useful succinic acid builders include the C5-C20 alkyl succinic acids and salts thereof. A particularly preferred compound of this type is dodecenylsuccinic acid. Alkyl succinic acids typically are of the general formula R—CH(COOH)CH₂(COOH) i.e., derivatives of succinic acid, wherein R is hydrocarbon, e.g., C₁₀-C₂₀ alkyl or alkenyl, preferably C₁₂-C₁₆ or wherein R may be substituted with hydroxyl, sulfo, sulfoxy or sulfone substituents, all as described in the above-mentioned patents.

[0076] The succinate builders are preferably used in the form of their water-soluble salts, including the sodium, potassium, ammonium and alkanolammonium salts.

[0077] Specific examples of succinate builders include: laurylsuccinate, myristylsuccinate, palmitylsuccinate, 2-dodecenylsuccinate (preferred), 2-pentadecenylsuccinate, and the like. Laurylsuccinates are the preferred builders of this group, and are described in European Patent Application 86200690.5/0 200 263, published Nov. 5, 1986.

[0078] Examples of useful builders also include sodium and potassium carboxymethyloxymalonate, carboxymethyloxysuccinate, cis-cyclo-hexanehexacarboxylate, cis-cyclopentane-tetracarboxylate, water-soluble polyacrylates and the copolymers of maleic anhydride with vinyl methyl ether or ethylene.

[0079] Other suitable polycarboxylates are the polyacetal carboxylates disclosed in U.S. Pat. No. 4,144,226, Crutchfield et al., issued Mar. 13, 1979, incorporated herein by reference. These polyacetal carboxylates can be prepared by bringing together, under polymerization conditions, an ester of glyoxylic acid and a polyerization initiator. The resulting polyacetal carboxylate ester is then attached to chemically stable end groups to stabilize the polyacetal carboxylate against rapid depolymerization in alkaline solution, converted to the corresponding salt, and added to a surfactant.

[0080] Polycarboxylate builders are also disclosed in U.S. Pat. No. 3,308,067, Diehl, issued Mar. 7, 1967, incorporated herein by reference. Such materials include the water-soluble salts of homo- and copolymers of aliphatic carboxylic acids such as maleic acid, itaconic acid, mesaconic acid, fumaric acid, aconitic acid, citraconic acid and methylenemalonic acid.

[0081] Suitable polyphosphonates for use herein are the alkali metal, ammonium and alkanolammonium salts of polyphosphates (exemplified by the tripolyphosphates, pyrophosphates, and glassy polymeric meta-phosphates), phosphonates. The most preferred builder for use herein is citrate.

Solvents

[0082] The compositions of the present invention may further comprise a solvent or a mixtures thereof where the composition is in liquid, gel or paste-type form. Solvents for use herein include all those known to the those skilled in the art of hard-surfaces cleaner compositions. Suitable solvents for use herein include ethers and diethers having from 4 to 14 carbon atoms, preferably from 6 to 12 carbon atoms, and more preferably from 8 to 10 carbon atoms, glycols or alkoxylated glycols, alkoxylated aromatic alcohols, aromatic alcohols, aliphatic branched alcohols, alkoxylated aliphatic branched alcohols, alkoxylated linear C1-C5 alcohols, linear C1-C5 alcohols, C8-C14 alkyl and cycloalkyl hydrocarbons and halohydrocarbons, C6-C16 glycol ethers and mixtures thereof.

[0083] Suitable glycols to be used herein are according to the formula HO—CR1R2—OH wherein R1 and R2 are independently H or a C2-C10 saturated or unsaturated aliphatic hydrocarbon chain and/or cyclic. Suitable glycols to be used herein are dodecaneglycol and/or propanediol.

[0084] Suitable alkoxylated glycols to be used herein are according to the formula R—(A)n—R1—OH wherein R is H, OH, a linear saturated or unsaturated alkyl of from 1 to 20 carbon atoms, preferably from 2 to 15 and more preferably from 2 to 10, wherein R1 is H or a linear saturated or unsaturated alkyl of from 1 to 20 carbon atoms, preferably from 2 to 15 and more preferably from 2 to 10, and A is an alkoxy group preferably ethoxy, methoxy, and/or propoxy and n is from 1 to 5, preferably 1 to 2. Suitable alkoxylated glycols to be used herein are methoxy octadecanol and/or ethoxyethoxyethanol.

[0085] Suitable alkoxylated aromatic alcohols to be used herein are according to the formula R (A)_(n)—OH wherein R is an alkyl substituted or non-alkyl substituted aryl group of from 1 to 20 carbon atoms, preferably from 2 to 15 and more preferably from 2 to 10, wherein A is an alkoxy group preferably butoxy, propoxy and/or ethoxy, and n is an integer of from 1 to 5, preferably 1 to 2. Suitable alkoxylated aromatic alcohols are benzoxyethanol and/or benzoxypropanol.

[0086] Suitable aromatic alcohols to be used herein are according to the formula R—OH wherein R is an alkyl substituted or non-alkyl substituted aryl group of from 1 to 20 carbon atoms, preferably from 1 to 15 and more preferably from 1 to 10. For example a suitable aromatic alcohol to be used herein is benzyl alcohol.

[0087] Suitable aliphatic branched alcohols to be used herein are according to the formula R—OH wherein R is a branched saturated or unsaturated alkyl group of from 1 to 20 carbon atoms, preferably from 2 to 15 and more preferably from 5 to 12. Particularly suitable aliphatic branched alcohols to be used herein include 2-ethylbutanol and/or 2-methylbutanol.

[0088] Suitable alkoxylated aliphatic branched alcohols to be used herein are according to the formula R (A)_(n)—OH wherein R is a branched saturated or unsaturated alkyl group of from 1 to 20 carbon atoms, preferably from 2 to 15 and more preferably from 5 to 12, wherein A is an alkoxy group preferably butoxy, propoxy and/or ethoxy, and n is an integer of from 1 to 5, preferably 1 to 2. Suitable alkoxylated aliphatic branched alcohols include 1-methylpropoxyethanol and/or 2-methylbutoxyethanol.

[0089] Suitable alkoxylated linear C1-C5 alcohols to be used herein are according to the formula R (A)_(n)—OH wherein R is a linear saturated or unsaturated alkyl group of from 1 to 5 carbon atoms, preferably from 2 to 4, wherein A is an alkoxy group preferably butoxy, propoxy and/or ethoxy, and n is an integer of from 1 to 5, preferably 1 to 2. Suitable alkoxylated aliphatic linear C1-C5 alcohols are butoxy propoxy propanol (n-BPP), butoxyethanol, butoxypropanol, ethoxyethanol or mixtures thereof. Butoxy propoxy propanol is commercially available under the trade name n-BPP® from Dow chemical.

[0090] Suitable linear C1-C5 alcohols to be used herein are according to the formula R—OH wherein R is a linear saturated or unsaturated alkyl group of from 1 to 5 carbon atoms, preferably from 2 to 4. Suitable linear C1-C5 alcohols are methanol, ethanol, propanol or mixtures thereof.

[0091] Other suitable solvents include butyl diglycol ether (BDGE), butyltriglycol ether, ter amilic alcohol and the like. Particularly preferred solvents to be used herein are butoxy propoxy propanol, butyl diglycol ether, benzyl alcohol, butoxypropanol, ethanol, methanol, isopropanol and mixtures thereof.

[0092] Typically, the compositions of the present invention comprise up to 20% by weight of the total composition of a solvent or mixtures thereof, preferably from 0.5% to 10% by weight and more preferably from 1% to 8%.

Bleaching Components

[0093] The compositions herein may also comprise a bleaching component. Suitable bleaching agents comprise any of those commonly referred to as peroxygen bleaches.

[0094] Suitable peroxygen bleaches for use herein include hydrogen peroxide or sources thereof. As used herein a source of hydrogen peroxide refers to any compound which produces active oxygen when said compound is in contact with water. Suitable water-soluble sources of hydrogen peroxide for use herein include percarbonates, preformed percarboxylic acids, persilicates, persulphates, perborates, organic and inorganic peroxides and/or hydroperoxides.

The Process of Treating a Hard-surface:

[0095] The present invention also encompasses a process of treating a hard-surface wherein the surface is contacted with a composition comprising a C1-6 carboxylic acid and an abrasive particulate component.

[0096] By “hard-surfaces”, it is meant herein any kind of surfaces typically found in houses like kitchens, bathrooms, or in car interiors or exteriors, e.g., floors, walls, tiles, windows, sinks, showers, shower plastified curtains, wash basins, WCs, dishes, fixtures and fittings and the like made of different materials like ceramic, vinyl, no-wax vinyl, linoleum, melamine, glass, any plastics, plastified wood, metal or any painted or varnished or sealed surface and the like. Hard-surfaces also include household appliances including, but not limited to, refrigerators, freezers, washing machines, automatic dryers, ovens, microwave ovens, dishwashers and so on.

[0097] Thus according to the process of treating a surface, the composition of the present invention is applied to the surface, preferably by either (i) applying the composition directly to the surface and then contacting the surface and composition with a cloth or sponge or other suitable application device or (ii) applying the composition to the cloth, sponge or other suitable application device and then contacting the surface with the application device and composition. In order to activate the rust removal performance, the composition must also come into contact with water, this can be achieved either by application of water to the surface or to the application device. In a preferred embodiment the composition is applied to a damp cloth, sponge or other suitable application device which is then used to treat the surface

EXAMPLES

[0098] The compositions of the present invention are exemplified by the present examples, which are not meant to be limiting. All amounts are represented as weight % of the total composition. Example HLAS (100% pure)  1.20% Perfume  0.15% Pigment  0.015% moisture  0.285% oxalic acid anhydrous 12.00% Calcium carbonate 86.35% Example 2 HLAS  1.20 Perfume  0.15% Pigment  0.015% moisture  0.285% oxalic acid dihydrate 16.7% silicagel  5% calcium carbonate 76.65% Example 3 and 4  3  4 CaCO3 69.34% 69.34% NaLAS  1.88%  1.88% oxalic acid anhydrous 22.5% 22.5% sodium acetate  1.28%  1.28% citric acid  5.0% — maleic acid —  5.0% Example 5 and 6  5  6 NaLAS  1.88%  1.88% Perfume  0.15%  0.15% sodium acetate  1.28%  1.28% sodium bisuphite  2.00% — ascorbic acid —  2.0% oxalic acid anhydrous 12.00% 12.0% Calcium carbonate 82.69% 82.69% Example 7  7 C₁₄₋₁₆ EO7  0.625% C₁₃₋₁₅ EO7  0.625% Perfume  0.15% Pigment  0.015% oxalic acid anhydrous 15.0% CaCO₃ 83.585%

[0099] The compositions above are typically prepared by mixing the calcium carbonate and all other ingredients with the exception of any acids to form a premix, allowing the premix to dry or actively drying the premix if necessary, to achieve a composition which contains less than 5% moisture. The substantially dry premix is then mixed with the oxalic acid to form a homogeneous composition.

[0100] Where pigment forms a component of the composition, a 5% solution of pigment in water is prepared and then mixed with a small proportion (approximately 10%) of the calcium carbonate. Equally when perfume is present in the composition it is also added to a small proportion of carbonate prior to mixing with the remaining ingredients.

[0101] In a preferred additional step after the addition of perfume and pigment where present in the composition, ±10% of the CaCO3 (calcium carbonate) is mixed with the HLAS until the surfactant and the carbonate are homogeneously mixed. 

What is claimed is:
 1. A scouring composition comprising a C1-6 carboxylic acid and an abrasive particulate component having hardness from 2 to 4 as measured according to the MOHS scale.
 2. A scouring composition according to any preceding claim wherein the composition is in particulate, liquid, gel or paste form.
 3. A scouring composition according to any preceding claim wherein the acid is selected from the group consisting of formic acid, sulphamic acid, hydroxyacetic acid, citric acid, fumaric acid, maleic acid, glycolic acid, lactic acid, thioglycolic acid, thiomalic acid, oxalic acid and mixtures thereof.
 4. A scouring composition according to any preceding claim wherein the acid is oxalic acid.
 5. A scouring composition according to any preceding claim wherein the acid is present at a level of from 8% to 16% by weight of the composition.
 6. A scouring composition according to any preceding claim wherein the abrasive component is calcium carbonate.
 7. A scouring composition according to any preceding claims wherein the abrasive is in particulate form having an average particle size in the range of from 5 to 100 microns.
 8. A scouring composition according to any preceding claims wherein the abrasive is present at a level if from 75% to 90% by weight of the composition.
 9. A scouring composition according to any preceding claims wherein the weight ratio of carboxylic acid to abrasive is in the range of 1:7 to 1:8.
 10. A scouring composition according to any preceding claim wherein the composition additionally comprises a surfactant.
 11. A scouring composition according to claim 10, wherein said surfactant is a mixture of nonionic surfactants.
 12. A process of manufacturing a composition according to any of the preceding claims comprising the steps of: a) premixing the abrasive and any wet or water-containing ingredients; b) drying the premix formed in the preceding step to achieve a composition having a moisture content of less than 10% water; and c) subsequently mixing the substantially dry premix formed in the preceding step with the carboxylic acid.
 13. A process according to claim 12 wherein the abrasive is calcium carbonate and the carboxylic acid is oxalic acid.
 14. A process of treating a hard surface comprising the steps of contacting the hard surface with a scouring composition comprising carboxylic acid and an abrasive according to any of claims 1 to
 11. 15. A process according to claim 14 wherein before and/or after treating the surface with the composition the surface is rinsed with water.
 16. A process according to either of claims 14 or 15 wherein the composition is applied using a cloth, sponge or other application device.
 17. The use of calcium carbonate as an abrasive in a scouring composition additionally comprising oxalic acid.
 18. The use according to claim 17 for removing rust stains from hard surfaces. 